Alone in a deserted house, he was so busy with his research work that he felt ________ lonely.
句意：他单独一人在这座废弃的房子里拼命埋头研究，一点也不觉得寂寞。anything but决不，一点也不。all but几乎，差一点。 nothing but仅仅，只是。故答案选C。